I agree with the others you should avoid the Soundblaster cards, they haven't done anything really innovative with their products in several years, and there are others that give you more bang for the buck.
My only warning about the Game Theater XP and Fortissimo II is that there have been some reports of people having problems passing DD and DTS with certain hardware and DVD software combinations. I haven't followed the issue too closely since I don't own one of these cards, but you may want to do some research and see if these issues have been resolved before purchasing.
If you don't mind spending a bit more money, you should look into the Midiman soundcards, either the Audiophile 24/96 or the Delta 410. These cards have very high-quality coax digital outputs, and they also have excellent quality DAC's for analog output, you may want to use for music playback. Depending on the quality of your receiver or pre/pro, these cards may actually have better-sounding DAC's.
The AP 24/96 is a 2-channel card, the Delta 410 has 7 analog-out channels, which can be useful for software decoding of DD/DTS. I'm also hopeful that in the future we'll see software playback solutions for DVD-A and/or SACD (the latter being less likely).
For ordering info on the Midiman soundcards, visit http://www.digitalconnection.com
For lots and lots of information about everything related to home theater computers, visit the HTPC forum at http://www.avsforum.com
Jeff
